VO2max, thresholds, and efficiency are thought to be and certainly do have considerable predictive power for endurance performance. They are great global variables to measure and monitor how an athlete is coping with the stress of long endurance athletics. However, most metabolic devices are bulky, require uncomfortable mouth pieces, backpacks, or other restrictive equipment which can interfere with an athlete’s performance. They also fail to directly measure the stress of arguably the most important organ during exercise, the skeletal muscle. Recently, the ability for skeletal muscle to utilize oxygen measured by near-infrared spectroscopy (NIRS) has been shown to the best predictor of endurance performance in trained cyclists. Therefore in order to gain the best picture of an athlete’s physiology, these global measures should be accompanied by devices that can measure local stress.
Introduction. In the last post how to complete a repeat desaturation protocol was discussed. This protocol is especially useful for multimodal and team sport athletes. Briefly, using a sport specific exercise modality, have an athlete complete repeated sprint intervals (~20s) until they can no longer desaturate or recover SmO2 to the same extent as the start of the workout. Using this data, coaches and athletes can get an idea of sprint endurance capacity which will inform substitution patterns in team sports activities and pacing strategies for other sports. In this blog post I want to walk through an example of a repeated desaturation protocol completed by a cyclist to get an idea of his capacity for accelerations/attacks during a race.
Over the last few blog posts, I have outlined how to Complete and Analyze a 5-1-5 Assessment. Briefly, a 5-1-5 assessment consists of progressively harder load steps where 5 minutes of work are followed by 1 minute of complete rest, then repeated. After the load is repeated twice it is increased until the athlete cannot finish a load or has completed sufficient work to gain enough information about their physiology. Using this data one of three major physiological limiters can be identified.
The last blog post discussed how to complete a 5-1-5 Assessment to evaluate which system: cardiac, pulmonary, or muscle oxidative capacity was most limiting to an athlete’s performance. In this post I will detail how to interpret the data to determine which system is most limiting. Upon completion of a 5-1-5 assessment, 2-3 graphs will need to be analyzed. 1) A total hemoglobin (THb) response graph which indicates how much blood is present underneath the sensor and 2) A muscle oxygen saturation (SmO2) response graph which indicates how much hemoglobin is oxygenated in the capillaries under the sensor. Optional: a third graph with heart rate response. Its typically more helpful to have the power/speed step graph overlaid with each graph to know when the power/speed is changing. Limitations are typically identified by trends in the THb and SmO2 response curves rather than by looking purely at the number values presented from the data. These trends help to identify the underlying physiology which then sheds light on the limitations being experienced during this assessment.
Purpose:The purpose of most physiologic testing is to find maximal or threshold values in order to better predict or dictate an athlete’s potential for performance. However, things like VO2max, the maximal amount of oxygen an athlete can uptake and utilize, is only predictive of performance across wide ranges of athlete prowess (Levine 2008). Determining threshold values, the point at which global-body homeostasis can no longer be maintained, may lend more credence to predicting an athlete’s performance (Heuberger et al. 2018) but in terms of dictating training, it is only a starting point. Determining threshold values allows for the simplification of training by creating training zones. However, it does not describe how the body is being limited during exercise. Endurance performance is primarily aerobic, therefore any process in which oxygen is up taken, transported, delivered, or consumed can be limiting to an athlete’s performance. There are three major systems that assist in aerobic metabolism, the pulmonary, cardiovascular, and skeletal muscle. Because of the inherent limitations with current testing protocols, the 5-1-5 Assessment was created. This assessment was designed to identify the greatest limiter (lungs, heart, or muscle) of an athlete’s physiology.